Sub-optimal variable length coding

Abstract

An apparatus and method for minimizing the code length of an input address for at least one for variable length encoded data is claimed. A block of variable length encoded data is read. The block of variable length encoded data is then converted into sub-optimall encoded data. The variable length encoded data is defined in having a prefix portion and a suffix portion. The prefix portion of the variable length encoded data is used to signify the look-up table. The suffix portion of the variable length encoded data is used as an input address for the look-up table.

1. A method for minimizing a code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 reading a block of variable length encoded data;  
 converting the block of variable length encoded data into sub-optimal encoded data, the variable length encoded data having a prefix portion and a suffix portion;  
 using the prefix portion of the variable length encoded data to signify the look-up table;  
 using the suffix portion of the variable length encoded data as an input address for the look-up table; and  
 retrieving data from the look-up table corresponding to the input address,  
 wherein converting the block of variable length encoded data into sub-optimal encoded data allows for retrieving data from the look-up table corresponding to the input address to occur in one clock cycle.  
 
   
   
     2. The method as set forth in  claim 1 , wherein a clock cycle is 74.25 MHz. 
   
   
     3. A method for minimizing the code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 reading a block of variable length encoded data;  
 converting the block of variable length encoded data into sub-optimal encoded data, the variable length encoded data having a prefix portion and a suffix portion;  
 using the prefix portion of the variable length encoded data to signify the look-up table; and  
 using the suffix portion of the variable length encoded data as an input address for the look-up table,  
 wherein there are three look-up tables,  
 wherein the three look-up table each comprises about 2 9  (512) entries.  
 
   
   
     4. A method for minimizing a code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 reading a block of variable length encoded data;  
 converting the block of variable length encoded data into sub-optimal encoded data, the variable length encoded data having a prefix portion and a suffix portion;  
 using the prefix portion of the variable length encoded data to signify the look-up table; and  
 using the suffix portion of the variable length encoded data as an input address for the look-up table,  
 wherein the variable length encoded data comprises a run length portion and a size portion, wherein the run length portion indicates a number of contiguous coefficients and the size portion indicates an AC value of the coefficients.  
 
   
   
     5. A method for minimizing a code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 reading a block of variable length encoded data;  
 converting the block of variable length encoded data into sub-optimal encoded data, the variable length encoded data having a prefix portion and a suffix portion;  
 using the prefix portion of the variable length encoded data to signify the look-up table; and  
 using the suffix portion of the variable length encoded data as an input address for the look-up table,  
 wherein converting the block of variable length encoded data into sub-optimal encoded data is done such that the length of the variable length encoded data that occurs most frequently is correlated to the code length.  
 
   
   
     6. An apparatus for minimizing a code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 a reader configured to read a block of variable length encoded data; and  
 a converter configured to convert the block of variable length encoded data into sub-optimal encoded data, the converter separating the variable length encoded data into a prefix portion and a suffix portion, wherein the prefix portion of the variable length encoded data is configured to signify a particular look-up table, and wherein the suffix portion of the variable length encoded data is configured as an input address for the particular look-up table.  
 wherein the converter is configured to convert the block of variable length encoded data into sub-optimal encoded data such that data may be retrieved from the look-up table corresponding to the input address in one clock cycle.  
 
   
   
     7. The apparatus as set forth in  claim 6 , wherein the clock cycle is 74.25 MHz. 
   
   
     8. An apparatus for minimizing the code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 a reader configured to read a block of variable length encoded data; and  
 a converter configured to convert the block of variable length encoded data into sub-optimal encoded data, the converter separating the variable length encoded data into a prefix portion and a suffix portion, wherein the prefix portion of the variable length encoded data is configured to signify a particular look-up table, and wherein the suffix portion of the variable length encoded data is configured as an input address for the particular look-up table,  
 wherein there are three look-up tables,  
 wherein the three look-up table each comprises about 2 9  (512) entries.  
 
   
   
     9. An apparatus for minimizing the code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 a reader configured to read a block of variable length encoded data; and a converter configured to convert the block of variable length encoded data into sub-optimal encoded data, the converter separating the variable length encoded data into a prefix portion and a suffix portion, wherein the prefix portion of the variable length encoded data is configured to signify a particular look-up table, and wherein the suffix portion of the variable length encoded data is configured as an input address for the particular look-up table,  
 wherein the variable length encoded data comprises a run length portion and a size portion, wherein the run length portion indicates a number of contiguous coefficients and the size portion indicates an AC value of the coefficients.  
 
   
   
     10. An apparatus for minimizing the code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 a reader configured to read a block of variable length encoded data; and  
 a converter configured to convert the block of variable length encoded data into sub-optimal encoded data, the converter separating the variable length encoded data into a prefix portion and a suffix portion, wherein the prefix portion of the variable length encoded data is configured to signify a particular look-up table, and wherein the suffix portion of the variable length encoded data is configured as an input address for the particular look-up table,  
 wherein the converter is configured such that the length of the variable length encoded data that occurs most frequently is correlated to the code length.  
 
   
   
     11. An apparatus for minimizing the code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 means for reading a block of variable length encoded data; and  
 means for converting the block of variable length encoded data into sub-optimal encoded data, the means for converting comprising means for separating the variable length encoded data into a prefix portion and a suffix portion, wherein the prefix portion of the variable length encoded data is configured to signify a particular look-up table, and wherein the suffix portion of the variable length encoded data is configured as an input address for the particular look-up table,  
 wherein the means for converting is configured to convert the block of variable length encoded data into sub-optimal encoded data such that data may be retrieved from the look-up table corresponding to the input address in one clock cycle.  
 
   
   
     12. The apparatus as set forth in  claim 11 , wherein the clock cycle is 74.25 MHz. 
   
   
     13. An apparatus for minimizing the code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 means for reading a block of variable length encoded data; and  
 means for converting the block of variable length encoded data into sub-optimal encoded data, the means for converting comprising means for separating the variable length encoded data into a prefix portion and a suffix portion, wherein the prefix portion of the variable length encoded data is configured to signify a particular look-up table, and wherein the suffix portion of the variable length encoded data is configured as an input address for the particular look-up table,  
 wherein there are three look-up tables,  
 wherein the three look-up table each comprises about 2 9  (512) entries.  
 
   
   
     14. An apparatus for minimizing the code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 means for reading a block of variable length encoded data; and  
 means for converting the block of variable length encoded data into sub-optimal encoded data, the means for converting comprising means for separating the variable length encoded data into a prefix portion and a suffix portion, wherein the prefix portion of the variable length encoded data is configured to signify a particular look-up table, and wherein the suffix portion of the variable length encoded data is configured as an input address for the particular look-up table,  
 wherein the variable length encoded data comprises a run length portion and a size portion, wherein the run length portion indicates a number of contiguous coefficients and the size portion indicates an AC value of the coefficients.  
 
   
   
     15. An apparatus for minimizing the code length of an input address for at least one look-up table for variable length encoded data, the method comprising:
 means for reading a block of variable length encoded data; and  
 means for converting the block of variable length encoded data into sub-optimal encoded data, the means for converting comprising means for separating the variable length encoded data into a prefix portion and a suffix portion, wherein the prefix portion of the variable length encoded data is configured to signify a particular look-up table, and wherein the suffix portion of the variable length encoded data is configured as an input address for the particular look-up table,  
 wherein the means for converting is configured such that the length of the variable length encoded data that occurs most frequently is correlated to the code length.